Cylinder Compression Pressure
Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8.7:1
Pressure Range. . . . . . . . . . . . . . .827 to 1,034 kPa
(120 to 150 psi)

CYLINDER COMPRESSION PRESSURE TESTThe results of a cylinder compression pressure test
can be utilized to diagnose several engine malfunctions.
Ensure the battery is completely charged and the
engine starter motor is in good operating condition.
Otherwise the indicated compression pressures may
not be valid for diagnosis purposes.
(1) Clean the spark plug recesses with compressed
air.
(2) Remove the spark plugs.
(3) Secure the throttle in the wide-open position.
(4) Disconnect the ignition coil.
(5) Insert a compression pressure gauge and rotate
the engine with the engine starter motor for three
revolutions.
(6) Record the compression pressure on the 3rd
revolution. Continue the test for the remaining cylinders.
Refer to Engine Specifications for the correct
engine compression pressures.

CYLINDER COMBUSTION PRESSURE LEAKAGE TEST
The combustion pressure leakage test provides an
accurate means for determining engine condition.
Combustion pressure leakage testing will detect:
† Exhaust and intake valve leaks (improper seating).
† Leaks between adjacent cylinders or into water
jacket.
† Any causes for combustion/compression pressure
loss.
(1) Check the coolant level and fill as required. DO
NOT install the radiator cap.
(2) Start and operate the engine until it attains
normal operating temperature, then turn the engine
OFF.(3) Remove the spark plugs.
(4) Remove the oil filler cap.
(5) Remove the air cleaner.
(6) Calibrate the tester according to the manufacturer’s
instructions. The shop air source for testing
should maintain 483 kPa (70 psi) minimum, 1 379
kPa (200 psi) maximum and 552 kPa (80 psi) recommended.
(7) Perform the test procedures on each cylinder
according to the tester manufacturer’s instructions.
While testing, listen for pressurized air escaping
through the throttle body, tailpipe and oil filler cap
opening. Check for bubbles in the radiator coolant.
All gauge pressure indications should be equal,
with no more than 25% leakage.
FOR EXAMPLE: At 552 kPa (80 psi) input pressure,
a minimum of 414 kPa (60 psi) should be maintained
in the cylinder.
Refer to the Cylinder Combustion Pressure Leakage
Test Diagnosis chart.